When the officer in charge of the ship was warned that an iceberg had been spotted in its path, he waited a crucial half-minute before changing course, a new study has concluded

Had William Murdoch taken action immediately, the liner – and 1,496 lives – might well have been saved.

The finding comes from major new study to coincide with the centenary of the Titanic disaster next year. Investigators have reappraised the original 1912 Wreck Commission inquiry in the light of all the research and evidence that has emerged since.

The new conclusion overturns the verdict of the original inquiry, which found that Murdoch, the First Officer, steered away immediately but could not avert catastrophe because the iceberg had been spotted too late.

Researchers now believe the reason Mr Murdoch hesitated before giving the order "hard a starboard" was that he thought the Titanic might be able to pass safely by the hazard, and that by altering direction he might increase the risk to the ship by swinging its stern towards the obstacle.

According to the 1912 inquiry findings, the iceberg was sighted about 1,500ft ahead of the ship and the collision followed 37 seconds later.

It found that the ship's course was altered "almost instantaneously" after the lookout rang a bell three times – the warning to signify an obstacle straight ahead – and telephoned the bridge below to say an iceberg had been spotted.

Until now, this has been the accepted version of events – and this is how it was depicted in the 1997 film Titanic, starring Leonardo DiCaprio and Kate Winslet.

However, the latest research establishes an exact timeline of the seconds before the collision, which reveals the iceberg was spotted when 2,000ft off – almost a minute before the impact – and that the ship held its course for around half of that time.

The researchers base this on the testimony of two individuals: Frederick Fleet, the lookout who sounded the alarm, and Robert Hichens, the sailor who was holding the steering wheel.

They also considered the witness statement of a third sailor, Albert Olliver, who described leaving his post when he first heard the bells and reaching the bridge just as the ship struck the iceberg.

Analysis of his route shows it would have taken him around 60 seconds.

Samuel Halpern, a US Titanic expert who has led the research, said: "If the First Officer had reacted sooner – maybe even 15 seconds sooner – the ship would have missed.

"I believe it was a delay so he could see whether the ship was going to miss the iceberg without the need for turning. It was a judgment call. And he misjudged.

"I don't think we can blame him. The First Officer was correct in trying to ascertain whether the ship was going to miss the iceberg by itself, which would have been the best approach, as [steering away] could have meant it hit further back."

The researchers found that Mr Murdoch had been involved in a similar incident on another ship, the Arabic, which narrowly missed another vessel in 1903 after he correctly decided to maintain course, rather than turn away.

The study is also supported by technical data – not fully available at the time – into the turning capacity of the ship, which established that it had been steering away from the iceberg for about 20 seconds before the collision.

Mr Murdoch died in the sinking. The testimonies of the other seamen were available to the investigators of 1912, but some of what they said was ignored.

Mr Halpern added: "The original inquiry gave more weight to the word of officers and people of higher rank than it did to regular seamen who were called to testify.

"I think the inquiry presented what they thought the First Officer would do, rather than what the testimony really indicated.

"I think they couldn't have imagined why he would not have immediately given the order as soon as the bell was struck. They just didn't take it into account."

After the collision, Mr Murdoch, 39, evacuated passengers and is credited with helping to launch ten lifeboats. He was last seen attempting to launch one, in the ship's final moments.

In the 1997 film, he is depicted committing suicide, having previously shot two passengers trying to storm one of the lifeboats.

There is no evidence to support this version of events, although survivors did report seeing him fire warning shots to stop people storming the boats.

The depiction prompted complaints in Mr Murdoch's home town of Dalbeattie, Dumfries and Galloway, which led James Cameron, the film's director, to provide a charitable prize there in his honour.

Rob Davidson, a local councillor for the area, said the new findings could reflect better on Mr Murdoch than the film did.

He said: "These new findings suggest the impression of someone reacting with calmness, going through all the options. Had the iceberg hit the stern first, it could have done more damage, and sunk faster."

Mr Halpern and 10 other researchers, from the UK, US, New Zealand and Australia, have together compiled the new work, Report into the loss of the SS Titanic: A Centennial Reappraisal, which also debunks a number of myths associated with the sinking.

These include:

– that the ship was doomed by a weak design and poor quality construction. In fact, no ship of the era could have withstood the seven-second contact with the iceberg, and it was the Titanic's immense strength that kept her afloat so long after the collision;

– that her rudder was "too small" for her size, meaning she could not turn sharply enough to avoid the obstacle.

– that the iceberg had not been spotted because the lookouts' binoculars were missing. Although true, the binoculars would not have been used to search for obstacles, but rather to evaluate their threat once they were seen.